Saw



I May 10,1927. 1,627,622

J. scHRr-:INER

Fild Deo. 21, 1925 Patented May 10,1927.

UETED STATES 1,627,622 PATENT OFFICE.

JOHN SCHREINER, OF CHICAGO, ILLINOIS, ASSIGNOR TO PAUL W. KOCII`& COMPANY,

OF CHICAGO, ILLINOIS, A CORPORATION OF ILLINOIS.

` SAW.

Application filed December 21, 1925. Serial No.776,623.

My invention relates to sawing mechanism and more particularly to an improved saw having a. plurality of blades for forming a plurality of slits at one time.

In the laying of electrical conduit across wooden joists, beams and other analogous members, I find it highly desirable to form pockets or notches in the aforesaid wooden members for receiving the conduit by lfirst cutting a plurality of parallel slits therein and then knocking out the material intermediate' the slits. n

In order to accomplish this both expedi# tiously and efficiently, I have invented and designed asaw for simultaneously cutting a plurality of slits. My saw includes briefly a plurality of spaced saw blades and means for varying the space separating the blades.

The object therefore of the present invention is to provide animproved saw for cutting a plurality of spaced slits contemv poraneously.

In the accompanying drawing,

Figure 1 is a plan view of my novel saw;

Figure 2 is a side view of the saw structure illustrated in Figure 1; l

Figure 3 is an enlarged sectional view taken on the line 3 3 of Figure 2 looking in the direction indicated by the arrows and illustrating how the saw is used;

Figure 4t is a sectional view taken on the line 4--4 of Figure 2 and enlarged like Figure 3, and A Figure 5 is an enlarged sectional view similar to Figure 3 but diering therefrom in that it illustrates the strengthening rib in a different position so as to increase the space separating the blades.

Referring now to the drawing in detail in which like reference numerals designate similar parts throughout the several views, 10 denotes a handle and 11 a holding device or guiding knob. The handle 10 is somewhat analogous to the handle employed on the usual plane and the knob `11 is also similar tothe guiding knob used on such planes.

Associated with the handle 10 and the knob 11 are a pair of saw blades 12 and 13 which, as I have illustrated in Figure 3, are

each preferably made two inches in width.'

In fact, the section illustrated in Figure 3 is actually drawn to full scale. The blades 12 and 13 are spaced at one end by the lowerportion 1&1 of the knob 11 and at the other In Figure 3, I have illustrated thev blades 12 and 13 in conjunction with ay wooden or beam member 16, which is beingslit thereby. Inasmuch as the ordinary type of standard conduit has an outside diameter of seven-eighths of an inch, I find it desirable to cut an aperture in the beam 16 approximately an inch in width and therefore space the blades 12 and 13 accordingly. The portion 17 of the wooden member' 16 intermediate the blades 12 and 13, as well as the slits formed in the member by the blades 12 and 13, is adapted to be knocked out by any suitable means such, for example, as a chisel. l

In order to give the blades the necessary rigidity, I provide the top edge of each of the blades with a U-shaped rib 20 which may be pressed thereon in any desirable manner. The ribs 20 are mounted upon the blades 12and 13 in much the same manner as the ribs are mounted on the saw bla-des of the so-called backed saws.

ingthe necessary rigidity to the blade,y but also limit the depth that the blade may penetrate into any member which it is desired to slit. 'Ihe ends of each rib 20 are cut in such a manner as to enable the saw blades 12 and 13 to engage the portions 141 and 15. As clearly shown in Figure 1, a portion 21 of each rib is cut away in order to form a shoulder 22. This enables 'the portion 14 of the knob 11 to abut the shoulders 22 at one end and to abut the blades 12 and 13 at its side. The portion 14 is thus enabled to cooperate wi'ththe ribs 2O through the shoulders 22 thereof to prevent undue strains and stresses from being imposed on the saw blades 12 and 13. A bolt 23 extends through one of the ribs 20, the blade 12, the port-ion 14 of the guiding knob 11 and is threaded at24 (Fig. 3), into both the blade 13 and the associated ribs 20. Another bolt 23 extends through the portion 14 of the knob 11 in the same manner as the bolt 23.

The other ends of the aforesaid ribs are cut in a similar manner to the previously described ends to form shoulders 22 which abut the portion 15 of the handle 10. The ends of the blades 12 and 13 are fastened i These ribs not` only afford a means of strengthening or giv-` to the portion 15 by bolts 23 in the same manner as the other' ends are fastened to the portion 14: by the bolts 23 and 23.

Now it is evident that the blades 12 and 13 are illustrated in Fig. 3 as beine spaced a distance apart sucient to enable them to cut a pair of slits in the member 16 approximately an inch apart. Also, it is obvious thatthe depth ot' the slits will be limited by the edges of the ribs 20. fitter thel slits have-been completed a portion 17 intermediate them is knocked out or removed bymeans of a chisel leaving a pocket in which a conduit havingan outside diameter of seVen-eighths of an inch may be laid.

In practice, approximately ninety per cent of the conduits used in buildings and other analogous structures are ot the size above mentioned. 'Ihe other ten percent of the conduits used is usually somewhat `larger having an outside diameter of one and oneeighth inches. In order to enable my blades 12 and 13 to outa pair ot slits spaced tur ther apart than those illustrated in Fig. 3 so as to enable theV forming ot a pocket to accommodate the one and one-eighth inch conduit, I provide means whereby the blades 12 and 13 may be yeasily removed Vfrom the holding members 10 and 11 and reversed in vposit-ion so that the distance between the blades is greater as is illustrated in Fig. 5.

In Fig. 5, the blades are shown spaced apart from each other a distance ol' about one and one-quarter inches. Obviously, after the slits have been formed in the beam or" joint member and the intermediate port-ion knocked out, an aperture or pocket will remain adequate to receive the larger size ot conduit. In order to space the blades 12 and 13 in this manner, all that is necessary to be done is to remove the blades from the holding devices 10 and 11 by removing the bolts associated therewith. rThen the position 01": the blades with respect to the holding members is reversed, so that instead ot the surface of each blade being flushed with the portions 1tand 15, the ribs are flushed therewith. This will result in the shoulders 22 and 22 being on the outside oit the tool. I have indicated the portions ot the ribs 20 abutting the portion 14 of the knob l1 in Figure 5 by the reference numeral 2G. rhe bolts are then inserted in the parts of the device and the blades 12 and 13 secured to the members 10 and 11.

In addition to varying' the spacing ot the saw blades 12 and 13, it is possible to vary the depth ot the slits formed by these blades by varying the width of the ribs 20. 'I'hat is to-say, by increasing or decreasing the legs of the U-shaped ribs 20, the distance that the saw blades may penetrate the member 1G may be varied. Then too, since the blades are very easily detached `from the holding devices l1 and 10, they may be replaced by new bladesfwhen worn out or by dil'lierent size blades whenever the occasion may demand the same. ylhus, itwill be seen that Ihave pro y'ided a rigidr tool or saw, the parts ot' which may be easily replaced or changed. The saw is one that is very economical to manufacture as well as 4one which will hold up tor a considerable period ofv time in practice.

I desire it understood that although I have illustrated and. described the preferred embodiment of my invention that the invention is not to be limited thereby, but only in so far as defined by the scope and spirit ot the claims hereto appended.

I claim 1. In a tool o't the class described, a pair ot parallel saw yblades, a pair o't'elements for spacing the" blades a given distance apart, one or said elements having associatedv therewith a handle, means for fastening the blades to the elements, and a rib associated with an edge of each of the blades t'or preventing llexing of the blades and torserving to limit the depth `of the cut by the said blades, each ot said ribs being formed in such a manner that by reversing saidblades the distance separating the blades may be varied. r

2. In a tool of the class described, a pair ot parallel saw blades, a pair of elements for spacing the 1 blades a given distance apart, means for 'fastening the blades to the elements, said elements comprising means adapted to be gripped manually to actuate the saw blades, and a rib associated with an edge ott each ot theblades, each of said ribs having each `end provided vwith a cut away portion to permit ot the corresponding spacing element to abut the side of the associated blade, said blades being-reversible to vary the distance separating them, said ribs being yadapted to be used to increase the said distance when said blades are reversed.

In witness whereof, I hereunto subscribe my name this 17th day of December, 1925.

JOI-IN SCHREINER. 

